Phagocytic cells are scavengers, disposing of abnormal cells (e.g., malignant cells), microorganisms, and miscellaneous particulated matter. We propose to investigate how these cells act upon the material they ingest. Two aspects of phagocytic cell function will be studied. The first aspect concerns the role of superoxide in the function of the granulocyte. Superoxide production by normal and leukemic granulocytes and by granulocytes from patients with familial defects in white cell function will be studied. Cell-free homogenates of granulocytes will be used to investigate the properties of the superoxide-generating system. Granulocyte superoxide dismutase will be sought. The role of superoxide in the bactericidal activity of granulocytes will be investigated by measuring the effect of dismutase on bacterial killing by these cells. The second aspect concerns the degradation by peritoneal macrophages and Kupffer cells of bacterial cell wall constituents. The spectrum and properties of the glycosidase activities of these cells will be surveyed. Natural substrates including lipopolysaccharide and peptidoglycan from bacteria will then be prepared and their degradation measured. With a mutant of E. coli whose cell wall can be specifically labeled with C14, the relationship between cell wall degradation and macrophage bactericidal activity will be investigated. The effect of prior phagocytosis on the cellular levels of the above-mentioned activities will be studied.